Manhole cover lock

ABSTRACT

A closure for a tank opening with an inwardly directed circumferentially extending catch flange comprising a cover adapted to seat over said opening, said cover having a filling passage and a vent passage therethrough, at least one latch shaft mounted on said cover for accessibiltiy on the upper side of said cover and extending downwardly to the underside of said cover, said latch shaft being mounted on said cover as aforesaid for movement longitudinally of its longitudinal axis and for movement of rotation about its longitudinal axis, yieldable resilient means urging said latch shaft longitudinally of itself and towards the underside of said cover, a latch extending radially of said latch shaft and having a series of locking flats in echelon arrangement, each locking flat being separated from its neighbouring locking flat by a shoulder, said latch shaft being mounted for rotation as aforesaid adjacent the edge of said cover and said series of locking flats being formed on said latch to cause the locus of the shoulder of each locking flat to cross the downward projection of the marginal portion of said cover in succession starting with the shoulder at the lower most locking flat as the shaft is rotated, a release-turn lever pivotally mounted adjacent the upper end of said latch shaft about an axis transverse to the longitudinal axis of said latch shaft and having a gripping end and a bearing end, a reaction surface on said cover for the bearing end of said lever, said gripping end of said lever being manually depressible to move said latch shaft downwardly against said yieldable means and being turnable to rotate said latch shaft about its longitudinal axis, said cover having a peripheral seal on its underside, said locking flats being adapted in use to engage with the inwardly directed flange of a manhole through manipulation of said release-turn lever.

United States Patent 1 Hunter i 1 MANHOLE COVER LOCK Edward W. Hunter,Port Franks, Canada [75] Inventor:

(73] Assignee: Emco Limited, London, Canada [22] Filed: June 24, 1974I21 Appl. No.: 482,744

[52] U.S. Cl. .i 220/324; 292/256.5; 220/246 [5|] Int. Cl. 365d 45/16[58] Field of Search 292/256, 256.5, 257; 85/3,

Primary [:Irumirwr-W. l. Price Ass-[slum E.\'amim'rR. E. Hart Almrncy,Agent, or FirmFetherstonhaugh & Co.

I 57 ABSTRACT A closure for a tank opening with an inwardly directedcircumferentially extending catch flange comprising a cover adapted toseat over said opening, said cover having a filling passage and a ventpassage therethrough, at least one latch shaft mounted on said l l June24, 1975 cover for accessibiltiy on the upper side of said cover andextending downwardly to the underside of said cover, said latch shaftbeing mounted on said cover as aforesaid for movement longitudinally ofits longitudinal axis and for movement of rotation about itslongitudinal axis, yieldable resilient means urging said latch shaftlongitudinally of itself and towards the underside of said cover, alatch extending radially of said latch shaft and having a series oflocking flats in echelon arrangement, each locking flat being separatedfrom its neighbouring locking flat by a shoulder, said latch shaft beingmounted for rotation as aforesaid adjacent the edge of said cover andsaid series of locking flats being formed on said latch to cause thelocus of the shoulder of each locking flat to cross the downwardprojection of the marginal portion of said cover in suc cession startingwith the shoulder at the lower most locking flat as the shaft isrotated. a release-turn lever pivotally mounted adjacent the upper endof said latch shaft about an axis transverse to the longitudinal axis ofsaid latch shaft and having a gripping end and a bearing end. a reactionsurface on said cover for the bearing end of said lever, said grippingend of said lever being manually depressible to move said latch shaftdownwardly against said yieldable means and being turnable to rotatesaid latch shaft about its longitudinal axis, said cover having aperipheral seal on its underside, said locking flats being adapted inuse to engage with the inwardly directed flange of a manhole throughmanipulation of said release-turn lever.

2 Claims, 8 Drawing Figures PATENTEDJUN 24 I975 SHEET PATENTEI] JUN 24ms SHEET MANHOLE COVER LOCK This invention relates to a closure for amanhole opening in the tank of a tank truck or the like.

Tanks on trucks that carry volatile substances such as gasoline areusually filled through a manhole opening at the top of the tank. ln thepast. it was common practice to leave the manhole opening open to theatmosphere as the truck was filled. This procedure gave rise toconsiderable pollution of the atmosphere as vapours were expelledthrough the manhole as the filling proceeded. In the more recent past.legislation has re quired collection of vapours from the manhole openingduring the filling process and covers for the manhole which provide forthe passage of a filler tube. the passage of a tube for vapour transferreturn or collection and for a marginal edge seal at the manhole openinghave been developed.

Various designs for the marginal edge seal have been devised, but therecontinues to be a want for a good locking mechanism that can beeffectively and quickly mounted in place on the various manhole designsthat are encountered in trucks. One of the difficulties with providingan effective seal has been the variation in design of the manholeopenings in the tanks. Openings have a downwardly extending catch flangeagainst which the seal lock catches. These flanges vary in depth fromtruck to truck and there has been difficulty in providing a securelocking mechanism of simple design that is effective for all flangedepths.

It is an object of this invention to provide a closure for a tankopening through which one can fill the tank and collect displacedvapours from the tank that has an effective locking mechanism that iseasily mounted and demounted on trucks of different manhole designs.

A closure for a tank opening with an inwardly directed circumferentiallyextending catch flange according to this invention comprises a coveradapted to seat over said opening. said cover having a filling passageand a vent passage therethrough. a latch shaft mounted on said cover foraccessibility on the upper side of said cover and extending downwardlyof the underside of said cover. said latch shaft being mounted on saidcover as aforesaid for movement longitudinally of its longitudinal axisand for movement of rotation about its longitudinal axis. yieldableresilient means urging said latch shaft longitudinally of itself andtowards the underside of said cover, a latch extending radially of saidlatch shaft and having a series of locking flats in echelon arrangement.each locking flat being separated from its next higher locking flat by ashoulder. said locking shaft being mounted for rotation as aforesaidadjacent the edge ofsaid cover and said series of locking flats beingformed on said latch to cause the locus of the shoulder of each lockingflat to cross the downward projection of the marginal portion of saidcover in succession starting with the shoulder of the lower most lockingflat. a release-turn lever pivotally mounted adjacent the upper end ofsaid latch shaft about an axis that is transverse to the longitudinalaxis of said latch shaft. said lever having a gripping end and a bearingend, a reaction surface on said cover for the hearing end of said lever,said gripping end of said lever being manually depressable to move saidlatch shaft downwardly against said yieldable resilient means and beingturnable to rotate said latch shaft about its longitudinal axis. saidcover having a peripheral seal on its underside. said locking flatsbeing adapted. in use, to engage with the inwardly directed flange of amanhole through manipulation of said release-turn lever.

The invention will be clearly understood after reference to thefollowing detailed specification read in conjunction with the drawings.

In the drawings:

FIG. 1 is an elevation of a closure according to the invention about tobe secured into place on a manhole opening of a tank;

FIG. 2 is a plan view of a closure according to the invention;

FIG. 3 is a sectional view illustrating the spring return arrangementand release-turn lever;

FIG. 4 is a perspective illustration of the latch;

FIGS. 5 and 6 are illustrations showing the latch revolved to a lockposition; and

FIGS. 7 and 8 are illustrations similar to FIGS. 5 and 6. but showingthe device locked at a different locking flat with a manhole flange oflesser dimension.

The numeral )0 refers to a closure for a manhole opening in the tank ofa tank truck or the like which is designed to carry a volatile substancesuch as gasoline. It has a top surface best seen in FIG. 2 and adownwardly extending flange 12 that is inserted into the manhole opening14 of the tank of a tank truck. The tank has not been fully illustratedbecause of its well known nature. The manhole opening 14. however. has adownwardly extending flange l6 and in use. it is customary to provide alocking means that has a latch that engages with the lower edge of theflange 16 to pull the closure downwardly against the opening andmaintain the peripheral seal 18 thereof in tight engagement with theupper edge of the flange l6. Filling ofthe tank takes place through filltube ll and venting of vapours takes place through vent tube 13 inaccordance with standard practice.

As indicated in the preamble to this invention, the flange l6 varies indepth from tank truck to tank truck and there has been difficulty inproviding a suitable latch design that will maintain a tight seal forall manhole flange designs. This invention fulfills that need in that itprovides a simple and reliable device capable of making a secure closureseal for various manhole designs that can be applied with a minimum ofeffort.

The flange 12 is cut away at the location of two similar latchassemblies that are manipulated from an inoperative position asillustrated in FIG. 2 to an operative position where they engage withthe underside of the flange 16 as will be described.

The latches 20 of the similar latch assemblies are each rigidly mountedon the free end ofa latch shaft 22 and secured thereto by means of a nut24. Latches 20 have a rectangular hole to receive the keyed free endportion of the shafts 22.

The latch shaft 22 in each case is mounted on the cover 10 within asleeve 26 that is welded to the cover and a compressed coil spring 28bears against a shoulder 30 at the lower end of the sleeve 26 and ashoulder on the shaft 22 as at 32 to normally urge the shaft in anupward direction.

Shaft 22 has a head 34 secured to its upper end by means of a pin 16.Numeral 38 is a seal to seal the shaft to its housing against the escapeof vapours of the tank in use. The upper end of the head 34 isbifurcated and a release-turn lever 40 is pivotally mounted therein bymeans of a pin 42. The short end of the lever 40 carries 3 a reactionwheel 44 that is adapted to rotate with respect to the shaft and thatbears against the reaction surface 46 of the sleeve 26.

It will be apparent that by manually depressing the free end of thelever 40 in the direction of the arrow 48, the latch shaft will bedepressed downwardly within the sleeve 26 against the pressure of thespring 28.

It will also be apparent that by rotating the lever about the axis ofthe latch shaft 22 the latch shaft can be rotated. In this respect, itwill be recalled that 44 is a wheel and rotates with respect to thelever to permit easy movement of the latch over the bearing surface 46.

The release operation of the lever 40 whereby the latch shaft can bedepressed in the direction of the arrow 50 by downward movement ofthcfree end of the lever in the direction 48 is illustrated in FIG. 3. Theturn action of the levers 40 whereby the latches can be rotated from aninoperative position illustrated in FIG. 2 to an operative positionwhere they underlie the edge of the flange 16 of a manhole opening isindicated by the arrows 52 in FIG. 2 of the drawings.

The design of the latch member 20 at its free end is illustrated in FIG.4. it consists of a series of locking flats 56 arranged from the bottomin echelon arrangement and separated one from the other by shoulders 58.As the levers 40 are rotated in the direction of ar rows 52, the locusof the shoulders 58 crosses the downward projection of the marginalportion of the cover 10 in succession starting with the lowermostshoulder so that the flats 56 will underlie in succession the lowermarginal edge of the flange 16 of the manhole opening until a shoulder58 engages the side of the flange 16. One of the shoulders 58 willengage the lower marginal portion of the flange 16 depending upon therelative height of the flange and latch member 20.

ln H0. 3, for example, it will be apparent that if one were to merelyrotate the lever 40 in the direction of arrows 52 the second shoulderfrom the bottom would engage with the flange l6 and the first lockingflat would underlie the flange 16. There would. however, be no lockingforce on the seal. In order to achieve a locking force, one woulddepress the handles 40 in the direction of arrow 48 to move the latchshaft downwardly of the position illustrated in FIG. 3 and then rotatethem in the direction of arrows 52. By this manner of operation, ashoulder higher than the first one would engage with the flange 16 toarrest rotation in direc tions 52 and when the levers 40 are released,spring 28 would force the shaft 22 in an upward direction to spring urgelatch flats against the bottom edge of the flange 16.

FIG. 5 is an illustration of the device locked to the manhole flange 16on the second locking flats from the bottom. in this case, therelease-turn levers 40 have been depressed in direction 48 to bring thesecond locking flat below the level of the flange l6 and then rotated indirection 52 to bring the respective locking shoulders in contact withthe marginal portion of the flange l6 and then released to permit thesprings 28 to lock the locking flats against the lower marginal edge ofthe flange.

FIGS. 7 and 8 show a flange 16 on a manhole cover that is of a lesserdepth in which case the lever 40 is rotated further to achieve a lockingfunction with a higher locking flat.

In use. the closure described is an integral part of the loading headwhich includes the fill pipe It and the va pour collection pipe 13 andthe entire assembly is carried by the free end ofthe loading arm. Thetank trucks pull up to the loading hay and the assembly head as described is swung into position above the open manhole in the top of thetank truck compartment. The loading arm is lowered until the head isonto the manhole collar and it is then clamped into position bydepressing and rotating the levers 40 as described. The fill pipe ll hasa ball joint generally indicated by the numeral for flexibility. Thejoint is indicated in a solid line and a dotted line position. It canassume either of these and many other positions to assist in properalignment.

It will be apparent that the release-turn levers which are firstoperated in a downward position to release or depress the latch againstthe pressure of the holding spring and then rotated to achieve interlockwith the flange provide an easy to operate and a positive latch formanholes having various depth flanges.

Embodiments of the invention other than the one described will beapparent to those skilled in the art.

What I claim as my invention is:

l. A closure for a tank opening with an inwardly directedcircumferentially extending catch flange comprising a cover adapted toseat over said opening. said cover having a filling passage and a ventpassage therethrough,

at least one latch shaft mounted on said cover for accessibility on theupper side of said cover and extending downwardly to the underside ofsaid cover,

said latch shaft being mounted on said cover as More said for movementlongitudinally of its longitudinal axis and for movement of rotationabout its longitudinal axis,

yieldable resilient means urging said latch shaft longitudinally ofitself and towards the underside of said cover,

a latch extending radially of said latch shaft and having a series oflocking flats in echelon arrangement, each locking flat being separatedfrom its neighbouring locking flat by a shoulder,

said latch shaft being mounted for rotation as aforesaid adjacent theedge of said cover and said series of locking flats being formed on saidlatch to cause the locus of the shoulder of each locking flat to crossthe downward projection of the marginal portion of said cover insuccession starting with the shoulder at the lower most locking flat asthe shaft is rotated.

a release-turn lever pivotally mounted adjacent the upper end of saidlatch shaft about an axis transverse to the longitudinal axis of saidlatch shaft and having a gripping end and a bearing end,

a reaction surface on said cover for the bearing end of said lever,

said gripping end of said lever being manually depressible to move saidlatch shaft downwardly against said yieldable means and being turnableto rotate said latch shaft about its longitudinal axis,

said cover having a peripheral seal on its underside,

said locking flats being adapted in use to engage with the inwardlydirected flange of a manhole through manipulation of said release-turnlever.

2. A closure for an opening with an inwardly directed circumferentiallyextending catch flange as claimed in claim I having two latch shafts.

said latch shafts being mounted for rotation as aforesaid in oppositedirections by their respective release-turn levers.

1. A closure for a tank opening with an inwardly directedcircumferentially extending catch flange comprising a cover adapted toseat over said opening, said cover having a filling passage and a ventpassage therethrough, at least one latch shaft mounted on said cover foraccessibility on the upper side of said cover and extending downwardlyto the underside of said cover, said latch shaft being mounted on saidcover as aforesaid for movement longitudinally of its longitudinal axisand for movement of rotation about its longitudinal axis, yieldableresilient means urging said latch shaft longitudinally of itself andtowards the underside of said cover, a latch extending radially of saidlatch shaft and having a series of locking flats in echelon arrangement,each locking flat being separated from its neighbouring locking flat bya shoulder, said latch shaft being mounted for rotation as aforesaidadjacent the edge of said cover and said series of locking flats beingformed on said latch to cause the locus of the shoulder of each lockingflat to cross the downward projection of the marginal portion of saidcover in succession starting with the shoulder at the lower most lockingflat as the shaft is rotated, a release-turn lever pivotally mountedadjacent the upper end of said latch shaft about an axis transverse tothe longitudinal axis of said latch shaft and having a gripping end anda bearing end, a reaction surface on said cover for the bearing end ofsaid lever, said gripping end of said lever being manually depressibleto move said latch shaft downwardly against said yieldable means andbeing turnable to rotate said latch shaft about its longitudinal axis,said cover having a peripheral seal on its underside, said locking flatsbeing adapted in use to engage with the inwardly directed flange of amanhole through manipulation of said release-turn lever.
 2. A closurefor an opening with an inwardly directed circumferentially extendingcatch flange as claimed in claim 1 having two latch shafts, said latchshaftS being mounted for rotation as aforesaid in opposite directions bytheir respective release-turn levers.